Perfect Pop Songs

Those with the kind of music, lyrics, performance, arrangement and production that you could easily repeat all day.

How about starting with this one? Somewhat outside of her usual cannon and none the worse for it. Perhaps also a contender for the sexiest vocals ever?

Louie Louie  by Julie London
When I hear "pop song", Katrina and the Waves "Walking on Sunshine" is what comes immediately to mind.  Sticks in the head all day.  I haven't heard of half the stuff you guys are listing.
Crimson and Clover - Tommy James & The Shondells
She's Not There - The Zombies
Pretty Lady - Lighthouse
I'm On Fire - Dwight Twilley Band
I Wanted To Tell You - Matthew Sweet
Wake Up Sleeping - The Saw Doctors

"Only the Lonely" The Motel"
"Stacy's Mom" Fountains of Wayne
Another vote for "God Only Knows"; I'd also add "Day After Day" by Badfinger.
A lot of great suggestions but--how about the most obvious. To me, the quintessential pop tunes as expressions of rebellion, teenage angst and/or lust are:

I Saw Her Standing There
 Like a Rolling Stone

Unlike many great pop songs, I have never tired of hearing these.

For a great sleeper:

Tighter, Tighter
by Alive and Kicking--Co-written, co-produced  and sung (one of the two vocalists on the record) by Tommy James